Reduced Friction Oil Sumps

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StevieC

StevieC

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Does anyone have good information on the differences between Reduce Friction oil sumps and regular wet sumps?

I'm assuming that instead of the crank slinging oil from the pan to the bottom end of the engine, oil from the pump is pumped to critical parts instead to reduce friction...
 
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I assume you're talking about dry sump vs. (conventional) wet sump. The idea with a dry sump is that there is no pool of oil standing below the crankshaft to be picked up and whirled around by wind coming off the crankshaft (called 'windage'). The added friction and unnecessary frothing of the oil comes from oil that is picked up and flung around by the wind vortex from the crank, NOT by the oil coming out of the crank and rod bearings and spraying around- that's the same regardless of sump type.

A windage tray in wet sump kinda does the same thing- it keeps the wind vortex from the spinning crank separated from the pool of oil in the bottom of the sump below the windage tray. Some are even made to "scrape" oil from the spinning vortex and direct it down to the pan. For pretty much any practical street engine, a wet sump with a windage tray is preferable to a full on dry sump and scavenge pump just because there's so much less complexity, and the advantage of the dry sump doesn't become really significant until you're sustaining very high RPM, or you're constantly cornering hard which might slosh the oil in a wet sump away from the oil pickup, or over the top of the windage tray. An exception is big air-cooled engines like old Porsches, where having a large remote oil tank and big oil coolers is very important to keeping the engine happy even in sustained straight highway driving.
 
No, I'm talking about wet reduced friction sump. I know about dry sumps and the scavenging pumps etc. My Yota is equipped with a "low friction oil sump" so half the bottom of the engine has no oil pan with just a small sump area where the oil pick-up sits and the oil resides.


Looks like this. It's too small to encompass the entire bottom of the engine.

[Linked Image]
 
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Originally Posted by StevieC
No, I'm talking about wet reduced friction sump. I know about dry sumps and the scavenging pumps etc. My Yota is equipped with a "low friction oil sump" so half the bottom of the engine has no oil pan with just a small sump area where the oil pick-up sits and the oil resides.


Looks like this. It's too small to encompass the entire bottom of the engine.



That's just a low-end approach to get some of the same effect as a real windage tray. It provides a pooling area that's partially separated from the crank windage.
 
That's what I thought... So I guess the piston cooling jets are the ones lubricating the areas that would normally be done by the crank slinging oil then.
 
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The crank still slings oil. All the oil coming out of the mains and out of the throws.
I don't know what they mean by friction. Odd choice of words.

Like Magnum stated there are pumping and windage losses to moving oil around.

That oil should be in the pan and nothing excessive picked from the counterweights or the chain unless you are making some high G moves or at an extreme attitude (pitch, roll).

Some of my small cars employed variable DISPLACEMENT oil pumps ( at any steady state rpm ) - - that is new stuff.

http://pumpvane.blogspot.com/2015/03/engine-oil-vane-pump-parts-such-as.html
 
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Originally Posted by StevieC
Does anyone have good information on the differences between Reduce Friction oil sumps and regular wet sumps?

I'm assuming that instead of the crank slinging oil from the pan to the bottom end of the engine, oil from the pump is pumped to critical parts instead to reduce friction...

Cranks haven't slung oil from the pan to the bottom of the engines as long as I have been alive. The cranks sling the oil that leaks from the crank and rod bearings.
 
Originally Posted by StevieC
That's what I thought... So I guess the piston cooling jets are the ones lubricating the areas that would normally be done by the crank slinging oil then.


The piston cooling jets just spray the bottoms of the pistons to lower temps and provide some additional lubrication to the walls, just like they do on engines with a full-length sump. Everything else in the setup you've depicted functions the same as on an engine with a full pan. As already noted, it's an attempt to gain some of the effects of a windage tray without the expense or complexity.
 
Yeah but the oil sprayed on the walls and the underneath of the pistons drips down onto the crank / counterweights that is what I was getting at.
 
Originally Posted by StevieC
Yeah but the oil sprayed on the walls and the underneath of the pistons drips down onto the crank / counterweights that is what I was getting at.


OK, but they do that on a normal engine too. The function is the same here. The only difference between this setup and a conventional one is the layout of the pan in an attempt to mitigate windage.
 
Originally Posted by Shannow
https://bobistheoilguy.com/forums/ubbthreads.php/topics/3692871/What_we_Holden_doing_-_sump_de

There's a paper I linked to there that explains low friction sup design (not low windage like racing engines)


I'm assuming this is the part that you are talking about?:

Quote
Nonetheless, the greatest benefits in fuel consumption following a cold start are achieved when the oil warm-up phase is shortened.The interaction of oil with the lower regions of the engine block was identified by different researchers as the main reason for the low rates of oil temperature rise. Jarrier[59] claimed that the interaction of the oil mist with the crankcase surfaces resulted in friction penalties of up to 5% over the NEDC. Law [70] investigated a novel sump design to increase the oil temperature stratification within the sump and feed hotter oil to the pump pick up.


And:

Quote
Heat transfer to the cylinder liners and block is small in comparison, around 10% of the total heat flow. The implication of this is that oil is in good thermal coupling with the lower parts of the engine structure which are in turn remote from the gas-side heat source. The large thermal capacity of the crankcase means this warms up slowest in the engine, and more importantly slower than the engine fluids.This is detrimental to the oil warm-up rate as it sinks heat from both the bearing films and bulk oil.


Paper is a good read, though I admit to breezing through it a bit. Per your allusion to the difference between low windage and low friction, I'd note that GM's been chasing low windage for quite a while and even in the engine family you mentioned
wink.gif


Do you have the "Hammerhead" style oil pan?
[Linked Image]


I assumed that was the one you might have given it seems to fit the description from your thread. Here's the NA version, which has a factory windage tray:
[Linked Image]


Interesting the two VERY different pans. Does yours also have the tray?
 
Yes, mine was the hammerhead one...hat's the one that I did my elevated RPM thermocouple down the dipstick tests.
 
Originally Posted by Shannow
Yes, mine was the hammerhead one...hat's the one that I did my elevated RPM thermocouple down the dipstick tests.


Thought so
thumbsup2.gif


Do you know if yours has a windage tray as well? Or is it assumed no, based on that pan design, which probably makes it unnecessary?
 
Techline TLLB or TLTD are the closest things I know you are talking about. TLTD would likely be the best, a lubricated thermal dispersant barrier. You'd sandblast the pan, spray the TLTD on, and then bake it at 350* for an hour. It will assist in oil drainback on whatever is coated, and also help transfer heat from the oil into the metal of what is coated, to keep temps down.

www.techlinecoatings.com ... Swain probably has something similar.
 
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